diff --git a/hkmc2/jvm/src/test/scala/hkmc2/BbmlDiffMaker.scala b/hkmc2/jvm/src/test/scala/hkmc2/BbmlDiffMaker.scala
index deea6994f..d2d322b4c 100644
--- a/hkmc2/jvm/src/test/scala/hkmc2/BbmlDiffMaker.scala
+++ b/hkmc2/jvm/src/test/scala/hkmc2/BbmlDiffMaker.scala
@@ -17,8 +17,10 @@ abstract class BbmlDiffMaker extends JSBackendDiffMaker:
       if isGlobal then typeCheck.disable.isGlobal = true
       typeCheck.disable.setCurrentValue(())
       if file =/= bbPreludeFile then
+        curCtx = Elaborator.State.init
         importFile(bbPreludeFile, verbose = false)
-  
+        curCtx = curCtx.nest(N)
+
   override def init(): Unit =
     if bbmlOpt.isSet then
       import syntax.*
diff --git a/hkmc2/shared/src/main/scala/hkmc2/bbml/bbML.scala b/hkmc2/shared/src/main/scala/hkmc2/bbml/bbML.scala
index 91e3881a1..14b7f0f9f 100644
--- a/hkmc2/shared/src/main/scala/hkmc2/bbml/bbML.scala
+++ b/hkmc2/shared/src/main/scala/hkmc2/bbml/bbML.scala
@@ -26,12 +26,7 @@ final case class BbCtx(
   env: HashMap[Uid[Symbol], GeneralType]
 ):
   def +=(p: Symbol -> GeneralType): Unit = env += p._1.uid -> p._2
-  def get(sym: Symbol): Option[GeneralType] =
-    if BbCtx.builtinOps(sym.nme) then ctx.get(s"#${sym.nme}") match
-      case S(Ctx.SelElem(_, _, symOpt)) => symOpt.flatMap(getImpl(_))
-      case _ => N
-    else getImpl(sym)
-  private def getImpl(sym: Symbol): Option[GeneralType] = env.get(sym.uid) orElse parent.dlof(_.getImpl(sym))(None)
+  def get(sym: Symbol): Option[GeneralType] = env.get(sym.uid) orElse parent.dlof(_.get(sym))(None)
   def getCls(name: Str): Option[TypeSymbol] =
     for
       elem <- ctx.get(name)
@@ -443,6 +438,8 @@ class BBTyper(using elState: Elaborator.State, tl: TL):
             goStats(stats)
           case (clsDef: ClassDef) :: stats =>
             goStats(stats)
+          case (modDef: ModuleDef) :: stats =>
+            goStats(stats)
           case Import(sym, pth) :: stats =>
             goStats(stats) // TODO:
         goStats(stats)
diff --git a/hkmc2/shared/src/main/scala/hkmc2/codegen/js/JSBuilder.scala b/hkmc2/shared/src/main/scala/hkmc2/codegen/js/JSBuilder.scala
index a69c4d0b5..eebdbd686 100644
--- a/hkmc2/shared/src/main/scala/hkmc2/codegen/js/JSBuilder.scala
+++ b/hkmc2/shared/src/main/scala/hkmc2/codegen/js/JSBuilder.scala
@@ -95,7 +95,7 @@ class JSBuilder(using Elaborator.State, Elaborator.Ctx) extends CodeBuilder:
     case Call(Value.Ref(l: BuiltinSymbol), args) =>
       err(msg"Illeal arity for builtin symbol '${l.nme}'")
     case Call(s @ Select(_, id), lhs :: rhs :: Nil) =>
-      Elaborator.ctx.Builtins.tryMapOp(id.name) match
+      Elaborator.ctx.Builtins.getBuiltinOp(id.name) match
         case S(jsOp) =>
           val res = doc"${result(lhs)} ${jsOp} ${result(rhs)}"
           if needsParens(jsOp) then doc"(${res})" else res
diff --git a/hkmc2/shared/src/main/scala/hkmc2/semantics/Elaborator.scala b/hkmc2/shared/src/main/scala/hkmc2/semantics/Elaborator.scala
index 6d4967dec..40437d60e 100644
--- a/hkmc2/shared/src/main/scala/hkmc2/semantics/Elaborator.scala
+++ b/hkmc2/shared/src/main/scala/hkmc2/semantics/Elaborator.scala
@@ -29,7 +29,10 @@ object Elaborator:
     ";" -> ",",
     "+." -> "+",
     "-." -> "-",
-    "*." -> "*")
+    "*." -> "*",
+    "/." -> "/")
+  private val builtinBinOps = aliasOps ++ (binaryOps.map: op =>
+    op -> op).toMap
 
   val reservedNames = binaryOps.toSet ++ aliasOps.keySet + "NaN" + "Infinity"
   
@@ -91,7 +94,7 @@ object Elaborator:
       val Num = assumeBuiltinCls("Num")
       val Str = assumeBuiltinCls("Str")
       val Predef = assumeBuiltinMod("Predef")
-      def tryMapOp(op: Str): Opt[Str] = aliasOps.get(op)
+      def getBuiltinOp(op: Str): Opt[Str] = if getBuiltin(op).isDefined then builtinBinOps.get(op) else N
   
   object Ctx:
     abstract class Elem:
diff --git a/hkmc2/shared/src/test/mlscript/bbml/bbPrelude.mls b/hkmc2/shared/src/test/mlscript/bbml/bbPrelude.mls
index d4916948c..193beb4ad 100644
--- a/hkmc2/shared/src/test/mlscript/bbml/bbPrelude.mls
+++ b/hkmc2/shared/src/test/mlscript/bbml/bbPrelude.mls
@@ -1,7 +1,15 @@
 // :bbml
 
+
+class Any
+class Nothing
+
 class Alloc
 
+class Bool
+class Int
+class Num
+
 class CodeBase[T, C, S]
 class Region[T]
 class Ref[T, S](reg: Region[T], value: S)
@@ -10,26 +18,28 @@ class Str(length: Int, concat: Str -> Str)
 
 class Error(msg: Str)
 
+declare module Predef
+
 fun run: [T] -> CodeBase[out T, out Nothing, out Any] -> T
 fun log: Str -> Any
 fun error: Nothing
 
-fun (#+): (Int, Int) -> Int
-fun (#-): (Int, Int) -> Int
-fun (#*): (Int, Int) -> Int
-fun (#/): (Int, Int) -> Num
+fun (+): (Int, Int) -> Int
+fun (-): (Int, Int) -> Int
+fun (*): (Int, Int) -> Int
+fun (/): (Int, Int) -> Num
 fun (+.): (Num, Num) -> Num
 fun (-.): (Num, Num) -> Num
 fun (*.): (Num, Num) -> Num
 fun (/.): (Num, Num) -> Num
 
-fun (#<): (Int, Int) -> Bool
-fun (#>): (Int, Int) -> Bool
-fun (#<=): (Int, Int) -> Bool
-fun (#>=): (Int, Int) -> Bool
-fun (#==): [T] -> (T, T) -> Bool
-fun (#!=): [T] -> (T, T) -> Bool
+fun (<): (Int, Int) -> Bool
+fun (>): (Int, Int) -> Bool
+fun (<=): (Int, Int) -> Bool
+fun (>=): (Int, Int) -> Bool
+fun (==): [T] -> (T, T) -> Bool
+fun (!=): [T] -> (T, T) -> Bool
 
-fun (#&&): (Bool, Bool) -> Bool
-fun (#||): (Bool, Bool) -> Bool
+fun (&&): (Bool, Bool) -> Bool
+fun (||): (Bool, Bool) -> Bool